Technical Field
The disclosure is related to liquid crystal display technology field, and more particular to a pixel cell driving circuit, a driving method and a pixel cell.
Related Art
The organic light-emitting diode (OLED) display panel, also known as the organic electric lighting display device, is an emerging flat-panel display component. The OLED display panel has the characteristics of simple preparation process, low cost, low power consumption, high lighting brightness, wide operating temperature range, light volume, and fast response. It is easy for the OLED display panel to implement a color display, a large screen display, and a flexible display and to match with the integrated circuit driver. Therefore in the flat-panel display field the OLED display panel has been widely used.
The pixel cells in the OLED display panel are typically arranged in a matrix, and according to the different driving manner, the OLED can be divided into two kinds as a passive-matrix OLED (PM-OLED) driving display panel and an active-matrix OLED (AM-OLED) driving display panel. Although the PM-OLED driving display panel has the simple process and low cost, but it exists the crossfeed, high power consumption, low life expectancy and other shortcomings. Therefore it is unable to meet the requirement of the high-resolution, and large-sized display. In contrast with the PM-OLED, each of the pixel cells in the AM-OLED driving display panel is equipped with a set of pixel cell driving circuit composed by a thin film transistor (TFT) and a storage capacitor and the control of the current of the OLED may be realized by controlling the TFT to turn on or turn off, thereby controlling the OLED to emit light. Since the driving circuit adds the TFT and the storage capacitor, such that the OLED in each of the pixel cells is able to emit light within a controllable frame time, and the driving circuit has small required driving current, low power consumption, and longer life, thereby meeting the requirement of the high-resolution, multi-gray scale, and large-sized display.
FIG. 1 is a schematic view of the pixel cell driving circuit of the OLED display device according to the current technology. T1 is the switch thin film transistor, T2 is the drive thin film transistor, Cs is the storage capacitor, the scanning line is used to provide the scanning signal, and the data line is used to provide the data signal. When the scanning signal provided by the scanning line is high level, a fixed voltage is applied to the gate g1 of the switch thin film transistor T1, such that the switch thin film transistor T1 enters a turn-on state, a voltage difference between the source s1 and the drain d1 of the switch thin film transistor T1 decrease to a small value, and the switch thin film transistor T1 may be similar to a short-circuited state. The data signal provided by the data line stores on the storage capacitor Cs through the switch thin film transistor T1, i.e. the storage capacitor Cs is charged. The thin film transistor T2 is connected to one terminal of the storage capacitor Cs, when the voltage of one terminal of the storage capacitor Cs is achieved to a turn-on voltage of the drive thin film transistor T2, the drive thin film transistor T2 is turned on to drive the OLED to emit light. When the scanning signal provided by the scanning line is low level, the switch thin film transistor T1 is at turn-off state; however, since the leakage current exists in the switch thin film transistor T1, the electrical charge on the storage capacitor Cs leaks to the data line along the switch thin film transistor T1 when the switch transistor T1 is at the turn-off state, such that the voltage of the storage capacitor Cs is dropped gradually, i.e. the transition voltage (as shown in FIG. 2) exists, and thus the voltage of the gate g2 of the drive thin film transistor T2 is dropped excessively when the switch thin film transistor T1 is at turn-off state, so as to cause the OLED display panel to flicker.